椰壳炭制备高表面活性炭活化方法比较

COMPARISON OF ACTIVATION METHODS FOR PREPARING SUPERACTIVATED CARBON FROM COCONUT SHELL CHARS

以海南产椰壳炭和越南产椰壳炭为原料,探讨多种活化方法对活性炭结构的影响.900℃下气相氧化、铁催化氧化均得到比表面高于2200m2g的活性炭.磷酸钾催化氧化制备的活性炭,微孔较少,比表面达2300m2g.越南椰壳炭的炭化程度低,KOH值接活化的产品微孔较少,中孔较多,比表面较低.用KOH活化海南椰壳炭,得到微孔发达的活性炭,中孔较多,但经过进一步炭化以后再用KOH活化,比表面积可以提高.KOH活化的收率高于气相氧化法.500℃下用磷酸、氯化锌活化越南炭化料,孔结构没有显著的变化.测定25℃下甲烷在活性炭样品上的吸附,表明甲烷吸附量随活性炭微孔比表面积的增大而增加.

Different activation methods were studied for the preparation of superactivated carbons.Coconut shell chars of two origins were the precursors.Active carbons of high surface area (>2000 m 2/g) were prepared at 900 ℃ by CO 2 oxidation.Fe catalyzed the oxidation but K 4P 2O 7 was found unfavorable for developing micropores.KOH is a good activation agent at 900 ℃.It needs less time of activation with a higher recovery of product than CO 2 oxidation.The higher degree of carbonization of the chars facilitates the development of micropores for the KOH activation.ZnCl 2 and H 3PO 4 activations were found invalid for carbonized coconut shells.It was proved that the adsorption capacity of carbons for methane at 25 ℃ and 3.5 MPa was affected by the surface area.